Retirement, Other Postretirement Benefits, And Defined Contribution Plans Plan Assets, Asset Allocations Targets (Details)	Dec. 31, 2020	Dec. 31, 2019
Domestic Equity Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	26.00%
Postretirement Asset Allocation	29.00%	29.00%
Domestic Equity Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	21.00%
Domestic Equity Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	31.00%
International Equity Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	18.00%
Postretirement Asset Allocation	18.00%	18.00%
International Equity Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	13.00%
International Equity Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	23.00%
Fixed Income Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	56.00%
Postretirement Asset Allocation	53.00%	53.00%
Fixed Income Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	51.00%
Fixed Income Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	61.00%
Other Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	0.00%
Postretirement Asset Allocation	0.00%	0.00%
Other Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	0.00%
Other Securities [Member] | Other Postretirement Taxable and Non-Taxable Assets [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	5.00%
Qualified Pension Plans [Member] | Domestic Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	39.00%
Postretirement Asset Allocation	38.00%	39.00%
Qualified Pension Plans [Member] | Domestic Equity Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	32.00%
Qualified Pension Plans [Member] | Domestic Equity Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	46.00%
Qualified Pension Plans [Member] | International Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	19.00%
Postretirement Asset Allocation	19.00%	19.00%
Qualified Pension Plans [Member] | International Equity Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	15.00%
Qualified Pension Plans [Member] | International Equity Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	23.00%
Qualified Pension Plans [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	42.00%
Postretirement Asset Allocation	42.00%	41.00%
Qualified Pension Plans [Member] | Fixed Income Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	39.00%
Qualified Pension Plans [Member] | Fixed Income Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	45.00%
Qualified Pension Plans [Member] | Other Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	0.00%
Postretirement Asset Allocation	1.00%	1.00%
Qualified Pension Plans [Member] | Other Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	0.00%
Qualified Pension Plans [Member] | Other Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target	10.00%